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Fin repair

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billdz

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The fins on some LPR rockets I purchased broke during shipping. Can I just glue the broken piece back on or do the fins need to be reinforced somehow?
Thanks,
B
 

TRFfan

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The fins on some LPR rockets I purchased broke during shipping. Can I just glue the broken piece back on or do the fins need to be reinforced somehow?
Thanks,
B
I dont think so. CA should be fine as long as the piece isnt too big.
 

GregGleason

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For most LPR rockets, wood glue is adequate. Don't slather it on. Put glue on both sides (just a skin of glue) and let it dry for about a minute, then put on another thin layer on each side then join them. It helps if you do it on a flat, non-stick surface (like parchment paper over a pane of glass). Hold it together for about 5 minutes then set another non-stick surface and place a weight on it (like a book). Let it cure for about 6 to 24 hours then it should be ready to place on the airframe.

If the fins extend beyond the airframe (the rocket lands on the fins, not the airframe) they will be stressed at landing. Reinforcement may not be a bad idea for all then fins if that is the case.

Greg
 

billdz

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Thanks for the replies. What about a piece of tape on both sides of the crack, with a layer of glue above and below the tape?
 

GregGleason

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Thanks for the replies. What about a piece of tape on both sides of the crack, with a layer of glue above and below the tape?
I'm assuming you are saying the tape is permanent part of the fin. If that is the case then I would not bother with tape. That's because tape has an irregular surface (not smooth) and the bond might not be that good. You are better off with paper. Paper needs a very very thin layer of Elmer's White glue (like spread with a old credit card), then applied to the fin. You just need something on top while it cures to resist warping. Make sure you give the part adequate air circulation as it require some amount of air to cure.

Greg
 
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